<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }
        html {
            height: 500px;
        }
        body {
            height: 1000px;
        }

        .box {
            /* position: relative; */
            margin: 10px;
            height: 200px;
            /* background-color: #eeeeee; */
        }

        p {
            color: white;
            font-size: 18px;
            line-height: 40px;
        }

        p:nth-child(1) {
            background-color: red; 
        }

        p:nth-child(2) {
            background-color: green;
            /* position: absolute; */
            /* top: 0; */
            /* left: 0; */
            bottom: 0;
            right: 0;
        }

        p:nth-child(3) {
            background-color: black;
        }
        .strong {
            position: absolute;
            top: 180px;
            left: 0;
            color: red;
        }
    </style>
</head>

<body>
    <div class="box">
        <p>前端小课，每日一课</p>
        <p>前端从0-1 <span class="strong">重要</span></p>
        <p>我们今天学习 position：absolute 布局</p>
    </div>
</body>

</html>